U.S. patent number 3,959,633 [Application Number 05/504,764] was granted by the patent office on 1976-05-25 for security guard recording system.
This patent grant is currently assigned to Merck & Co., Inc.. Invention is credited to William Grove Lawrence, Wolfgang Juergen Sauter.
United States Patent |
3,959,633 |
Lawrence , et al. |
May 25, 1976 |
Security guard recording system
Abstract
A watchman's tour recording system which includes a watchman's
unit having a clock means for producing digital time signals, a
station identification signal producing means for producing digital
station signals, at least two digital bit storage or memory means
and special address means arranged to direct the digital time and
station identification signals into predetermined locations in the
memory means so that their storage capabilities are most
effectively utilized. Novel photoelectric station identification
signal generating means are also disclosed.
Inventors: |
Lawrence; William Grove (Santa
Ana, CA), Sauter; Wolfgang Juergen (Fountain Valley,
CA) |
Assignee: |
Merck & Co., Inc. (Rahway,
NJ)
|
Family
ID: |
24007636 |
Appl.
No.: |
05/504,764 |
Filed: |
September 10, 1974 |
Current U.S.
Class: |
377/20; 235/474;
340/306; 235/459; 235/482; 346/52 |
Current CPC
Class: |
G07C
1/20 (20130101) |
Current International
Class: |
G07C
1/00 (20060101); G07C 1/20 (20060101); G08B
029/00 () |
Field of
Search: |
;340/149A,306,172.5
;235/61.7B,61.11E,61.6H,92T ;346/60,52 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Boudreau; Leo H.
Attorney, Agent or Firm: Westlake, Jr.; Harry E. Anderson,
Jr.; Rudolph J. Katz; Martin L.
Claims
What is claimed and desired to be secured by Letters Patent is:
1. A watchman's unit for recording correlated time and station
identity information during a watchman's tour, said unit
comprising
clock signal means operable, upon connection of the unit to a
station, to produce clock signals representative of elapsed time
from the start of a tour,
station identity signal means operative, upon connection of the
unit to a station, to produce station signals representative of the
identity of the station,
clock signal storage means and station signal storage means for
storing the signals produced by said clock signal means and said
station identity signal means respectively,
at least one of said signal means being operative to produce
signals in the form of binary coded digital words each made up of a
predetermined number of bits,
the signal storage means associated with said one signal means
having a plurality of digital bit storage elements at various
locations therein for storing the bit data of a multiplicity of
said digital words,
address means connected to the signal storage means associated with
said one signal means and operative sequentially to render
different one of said digital bit storage elements receptive to
applied digital bit data, and
decoder means connected to the output of said one signal means and
operative sequentially to transmit different bits of a binary coded
digital word signal being produced to its associated signal storage
means,
said address means and said decoder means being arranged to be
operated in synchronism.
2. A watchman's unit according to claim 1 wherein said one signal
means includes a register having different stages for retaining
said predetermined number of bits, said decoder means and said
address means being arranged to be scanned in synchronism.
3. A watchman's unit according to claim 2 wherein said decoder
means is connected to scan said register repeatedly during each
scan of said address means.
4. A watchman's unit according to claim 1 wherein said address
means comprises a counter having a count capacity equal to that of
the signal storage means to which it is connected and wherein said
counter has output terminals which become energized according to a
pattern representative of the number of scanning pulses applied
thereto, said output terminals being connected to said storage
means to render said digital bit storage elements receptive to
applied digital bit data according to the number of scanning pulses
applied to said counter.
5. A watchman's unit according to claim 1 wherein said decoder is
connected to selected output terminals of said address means.
6. A watchman's unit according to claim 1 wherein said address
means becomes energized according to a binary counting sequence as
successive scanning pulses are applied to it and wherein the
outputs representative of the least significant digit of said
digital bit data in said address means are connected to said
decoder means in a manner such that the decoder produces an output
on a single output line in accordance with the state of a stage
therein corresponding to the pattern of energization of said least
significant data outputs.
7. A watchman's unit according to claim 1 wherein said unit
includes means for causing a series of scanning impulses of said
predetermined number to be supplied to said address means in
response to the connection of said unit to a station to be
checked.
8. A watchman's unit according to claim 7 wherein said means for
causing a series of scanning impulses includes said clock signal
means.
9. A watchman's unit according to claim 1 wherein said decoder
means includes plural decoder units each having inputs connected to
different bit output terminals of said one signal means and wherein
said storage means includes plural storage units each having a data
input terminal connected to the output of a different one of said
decoder units, said address means being connected to each of said
plural storage units for simultaneous control of said units.
10. A watchman's unit according to claim 9 wherein said plural
decoder units are connected to be operated simultaneously in
synchronism with said address means.
11. A watchman's unit for recording correlated time and station
identification information during a watchman's tour, said unit
comprising
a first signal storage means,
a station input device responsive upon connection to a station to
supply station identity signals to said first signal storage
means,
a second signal storage means having a first plurality of digital
bit storage locations for storing information in binary digital
code,
digital clock means operative to produce a series of timed
pulses,
time data means comprising a register for accumulating said pulses
and having a second plurality of output terminals which become
energized according to patterns corresponding to the number of
accumulated pulses,
time data decoding means connected to said output terminals, said
decoding means having a time data output terminal connected to said
second signal storage means and operative in response to each of
successively applied pulses to pass the signal present at a
different one of the register output terminals through said time
data output terminal for application to said second signal storage
means,
address means connected to said second signal storage means and
operative in response to each of successively applied pulses to
render a different one of said digital bit locations receptive to
applied time data signals, and
means for applying pulses to operate said time data decoding means
and said address means in synchronism with each other in response
to connection of said unit to a station.
12. A watchman's unit according to claim 11 wherein the first
plurality of digital bit locations in said second signal storage
means is a multiple of said second plurality of output terminals of
said time data means register.
13. A watchman's unit according to claim 11 wherein said digital
clock means is connected through a gate to said address means,
means for opening said gate in response to the connection of said
unit to a station to be checked and means for closing said gate in
response to the passing therethrough of pulses equal in number to
said second plurality.
14. A watchman's unit according to claim 11 wherein said second
signal storage means comprises a plurality of memory units each
having a number of digital bit locations.
15. A watchman's unit according to claim 11 wherein said station
input device comprises means having a plurality of station
identification terminals equal in number to said second plurality
and means for energizing said station identification terminals
according to a binary digital code representative of the identity
of a station to which the watchman's unit is connected.
16. A watchman's unit according to claim 15 wherein said first
signal storage means also has a number of digital bit storage
locations equal in number to said first plurality and wherein
further data decoding means are connected to said station
identification terminals, said further data decoding means having a
station identification data output terminal connected to said first
signal storage means.
17. A watchman's unit according to claim 16 wherein a further
address means is connected to said first signal storage means, said
further address means connected to be operated in response to each
of said successively applied pulses.
18. A watchman's unit according to claim 17 wherein said further
data decoding means is connected to be scanned in synchronism with
said further address means.
19. A watchman's unit according to claim 18 wherein said time data
decoding means and said further data decoding means have equal
numbers of inputs.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to security systems and more particularly it
concerns novel arrangements for recording and checking security
tours made by watchmen.
2. Description of the Prior Art
In carrying out security checking operations in factories or other
commercial establishments, watchmen usually follow a prearranged
tour so that critical areas are checked at predetermined intervals
and so that a complete coverage of the premises can be ensured. It
is important for insurance and other purposes to have a record made
of the watchman's tour. In the past this was obtained by providing
the watchman with a self-contained recording unit which included a
clock and a disc shaped paper which was rotated by the clock. The
recording unit was "punched" or connected to special station keys
at preselected locations along the watchman's tour. As each punch
was made, the key would make an impression on the paper disc. This
impression was in the form of a symbol which corresponded to the
identity of the station; and the location of the symbol on the
disc, which was rotated by the clock, would correspond to the time
that station was checked. After the tour had been completed, the
paper disc would be removed from the unit and replaced by a new
one. By noting the symbols and their locations on the disc, it was
possible to ascertain what stations were checked and at what times
and in what order they were checked.
While this system provided a permanent record of the watchman's
tour, it was limited, from a practical standpoint, to relatively
simple tours involving a small number of stations. Where a greater
number of stations are involved the process of checking the
recorded discs becomes very time consuming and subject to error.
Also, the system does not lend itself to the checking of multiple
tours, nor is it readily adaptable to tour modifications.
It has been proposed to utilize electronic means and a computer
system to overcome the above described limitations of the
conventional watchman's clock system. Such proposals are found, for
example, in U.S. Pat. Nos. 1,919,007; 2,275,981; 2,308,198;
2,734,791; 3,237,183; 3,371,349 and 3,736,561. These electronic
means, however, involved the wiring of each station to be checked
to a central computer. While these electronic systems would produce
an instantaneous computer readable indication of each station check
made by a watchman, they suffer from the disadvantage that the
wiring involved makes them quite expensive. Also, a wired system
does not lend itself to tour modification.
In another invention, described and claimed in U.S. application
Ser. No. 504,765 filed, Sept. 10, 1974 it is possible to provide
one or several tours convering a great number of stations; and
these tours may be reported and checked accurately and rapidly with
computer means.
According to the last mentioned invention there is provided a tour
recording arrangement which is carried in a watchman's unit. This
tour recording arrangement includes a clock signal producing means,
a station identification signal producing means, a signal storage
or memory device and means for directing corresponding clock and
station identification signals to predetermined locations in the
memory device each time the watchman connects the unit to a station
being checked. Unlike the clock rotated paper disc units of the
prior art, the clock signals in this last mentioned invention are
recorded as actual data in predetermined locations in the memory
device. Thereafter, at the end of a tour the watchman's unit may
simply be plugged into a terminal and the data stored in its memory
device can be read out to provide a complete, accurate and
instantaneous report of the tour along with an indication of missed
or improperly checked stations or stations checked at the wrong
time.
According to one embodiment of this last mentioned invention, the
station identification signals direct the clock signals to
corresponding locations in the memory device. In another
embodiment, the memory device is of sufficient capacity to receive
and store both clock signals and station identification signals. In
this second embodiment there are provided sequencing means which,
upon each station check directs the station identification and
clock signals to corresponding locations in the memory device.
SUMMARY OF THE INVENTION
The present invention provides improvements which are useful in
connection with the invention of U.S. application Ser. No. 504,765.
According to one aspect of the present invention there are provided
novel check stations and watchman's unit arrangements for
generating digital code signals representing the identity of a
station to be checked. These novel arrangements include a light
source extending along one side of a slot in a watchman's unit and
a plurality of photocells positioned along the opposite side of the
slot and facing the light source. These photocells are individually
capable of producing electrical signals on associated output
terminals when exposed to light from the light source. A card is
provided at each station to be checked; and this card has a series
of holes, which, when the card is filled into the slot in the
watchman's unit, extend between the photocells and the light source
in alignment with each photocell. Some of the holes are filled with
a light transparent substance and others are filled with a light
opaque substance according to a pattern which corresponds to the
station's identity. When the card is inserted into the slot in the
watchman' s unit, the light source turns on and those photocells
which are aligned with the light transparent holes in the card
become energized to produce signals while the other photocells
remain unenergized. This arrangement avoids mechanical contact
between electrical parts of the card and the watchman's unit so
that wear is reduced and reliability is increased.
According to another aspect of the invention there are provided
novel signal storage and processing arrangements within a
watchman's unit which permits maximum use of the storage capacity
of memory units used in the system. More particularly, storage unit
address means are scanned in synchronism with registers containing
station identification and time data words; and means are provided
to continue the storage scan while the registers are scanned
repeatedly as successive station checks are made. The present
invention, in this aspect, comprises a first signal storage means,
and a station input device responsive upon connection to a station
to store station identity signals in the first signal storage
means. There is also provided a second signal storage means having
a plurality of digital bit locations for storing digitally coded
information as well as digital clock means operative to produce a
series of timed pulses. Time data means are provided comprising a
register for accumulating the digital clock pulses and for
energizing plural output terminals in patterns corresponding to the
number of accumulated pulses. Time data decoding means are
connected to these output terminals. The time data decoding means
has a time data output terminal connected to the second signal
storage means and the time data decoding means operates in response
to each of successively applied pulses to pass the signals present
at a different one of the register output terminals through the
time data output terminal for application to the second signal
storage means. Address means are connected to the second signal
storage means and are operative in response to each of successively
applied pulses to render a different one of the digital bit
locations in the signal storage means receptive to applied time
data signals. Finally, means are provided for applying pulses to
operate the time data decoding means and address means in
synchronism when the unit is connected to a station.
There has thus been outlined broadly the more important features of
the invention in order that the detailed description thereof that
follows may be better understood, and in order that the present
contribution to the art may be better appreciated. There are, of
course, additional features of the invention that will be described
more fully hereinafter. Those skilled in the art will appreciate
that the conception on which this disclosure is based may readily
be utilized as the basis of the designing of other methods and
structures for carrying out the purposes of this invention. It is
important, therefore, that this disclosure be regarded as including
such equivalent constructions as do not depart from the spirit and
scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention has been chosen for
purposes of illustration and description, and is shown in the
accompanying drawings forming a part of the specification,
wherein;
FIG. 1 is a diagrammatic representation of a watchman's tour route
in which the present invention is utilized;
FIG. 2 is a block diagram showing a computer, computer terminal and
watchman's unit in which the present invention is embodied;
FIG. 3 is a perspective view of the watchman's unit in which the
present invention is embodied;
FIG. 4 is a partially exposed perspective view showing the exterior
of a station to be checked by the watchman's unit of FIG. 3;
FIG. 5 is a partially exposed perspective view showing the interior
of the station of FIG. 4; and
FIG. 6 is a block diagram showing the interior arrangement of
components in the watchman's unit of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, a premises to be protected is indicated schematically by
an outline 10. Within the premises there is provided a terminal
station 12 from which various guard tours start and end. Also
within the premises are several check stations 100-113. The number
and location of these stations is preselected in accordance with
the particular security requirements of the premises.
In conducting a tour, a watchman begins at the terminal station 12;
and then he walks along a preassigned route, as indicated by the
dashed lines 13, to preselected ones of the check stations. At each
station the watchman connects a station key to a watchman's unit
which he carries with him. This provides a recording in the
watchman's unit of the time and station identifying of each check
which he makes.
The number of stations to be checked in each tour, the order in
which stations are checked and the times they are to be checked are
established before the watchman's tour begins. For the purpose of
maximizing security within the premises, the tour routes are
changed periodically. It is the ability to adapt to various tour
changes which constitutes one important feature of the present
invention.
Upon completion of his tour the watchman returns to the terminal
station 12 where, as shown in FIG. 2, there is provided a terminal
board 14 having a connector plug 16 thereon. A watchman's unit 18
is shown connected to the terminal board 14 via the connector plug
16. When the watchman completes his tour he connects his unit 18 to
the terminal board 14; and the data representative of the stations
checked and the time of each check made during the tour is fed from
the watchman's unit 18 into the terminal board 14. The terminal
board 14 is shown to be connected via a cable 19 to a central
computer 20. This computer may be remotely located or it may be
located at the terminal station 12. A tour storage bank 22 is
provided in association with the computer 20. The tour storage bank
22 contains information representative of the stations to be
checked for each of several predetermined tours. When a watchman's
unit 18 is connected to the terminal board 14 to feed actual tour
data through the board into the computer 20, ideal data for that
particular tour is also fed into the computer from the tour storage
bank 22. The actual tour data and the ideal tour data are compared
in the computer and any discrepancies which exist are noted and
reported. This report may take the form of a printout at the
terminal board 14 as indicated at 24 in FIG. 2.
The watchman's unit 18 is a smaller electronic device which, as
shown in FIG. 3, externally resembles a small portable radio. The
unit is provided on the top thereof with a terminal connector slot
26 and, on the bottom thereof a station connector slot 28 into
which various plugs, such as the connector plug 16 on the terminal
board 14 and corresponding plugs at the various stations 100-113
are inserted for reading data into and out from the unit. The unit
18 is also provided with a switch dial 30 which may be turned to
any of several positions corresponding to different tours to which
the unit may be assigned. A tour identification number,
corresponding to the setting of the dial switch 30 appears at a
window 32 at the side of the unit. An operation light 33 is also
provided on one side of the unit 18 to indicate when data
transferred into or out from the unit is complete.
In carrying out a tour, a watchman proceeds from the terminal
station 12 and follows a route corresponding to the tour to which
his unit 18 has been set. This tour requires that the watchman be
present at particular ones of the check stations 100-113 at
predetermined times. The presence of the watchman at each station
is recorded in his unit when he inserts a station plug into the
station connector slot 28 of the unit 18.
As shown in FIG. 3, there is provided inside the watchman's unit 18
a light source 40 extending along one side of the station connector
slot 28 and a plurality of photocells 42 distributed along the
other side of the slot. A pair of connector switch photocells 42a
and 42b are provided, one at each end of the line of photocells 42.
Also, there are provided pulsing light sources 40a and 40b at each
end of the light source 40 in alignment with the connector switch
photocells 42a and 42b respectively. A guide lug 46 is also
provided near the lower edge of the unit to prevent improper
placement of station keys in the slot.
FIG. 4 shows a station connector key arrangement for checking by
the watchman's unit 18. This station key arrangement comprises a
base plate 48 having holes 50 near each end through which bolts or
rivets 52 pass to anchor the arrangement to a structural member or
other solid anchor means at a predetermined location in the
premises to be checked. A box-like housing 54 is attached to the
base plate 48. This housing is opened at the top and is shaped to
allow the lower end of the unit 18 to fit down into it. The front
side of the housing 54 is notched at 55 to accomodate the guide lug
46 of the watchman's unit. An identification numeral may be printed
on the front of the housing for visual identification of the
station.
FIG. 5 shows a station connector assembly 56 which fits into the
bottom of the box-like housing 54 of FIG. 4. The connector assembly
56 includes a horizontal bottom plate 58 which fits up against and
closes the bottom of the housing 54. The bottom plate 58 is held in
place by means of screws 60.
A card like connector element 62 extends upwardly from the center
of the bottom plate 58 within the housing 54. As shown in FIG. 5
this connector element is provided with a series of spaced apart
holes 64, some of which are filled with a light transparent
substance and others of which are filled with a light opaque
substance. The particular arrangement of light transparent and
light opaque holes forms a binary coding arrangement which
identifies the station. Notches 64a and 64b are formed along the
upper edge of the connector element 62. These notches are arranged
to be in alignment with the connector switch photocells 42a and 42b
and their respective pulsing light sources 40a and 40b when the
connector element 62 is fitted into the slots 28 of the watchman's
unit 18. It will be noted that the notches 64a and 64b do not
exceed down to the level of the holes 64. These notches thus serve
to prevent blocking of the light from the pulsing light sources 40a
and 40b to their respective connector switch photocells 42a and 42b
as the connector element 62 is initially being inserted into the
unit 18.
The coding arrangement of the connector element 62 is not readily
visible so that it is not susceptible to counterfeiting should a
watchman wish to enter false data into the recorder unit. In
addition the particular code for the station may be changed by
removing the bottom plate and connector unit and replacing it with
a new one. A wire 66 may be passed through holes in the screws 60
and fastened with a seal 68 to prevent surreptitious removal of the
bottom plate and connector element.
In making a station check, the watchman's unit 18 is fitted into
the box-like housing 54 at the station so that the connector
element 62 fits into the station connector slot 28, so that the
holes 64 become positioned between the light source 40 and the
various photocells 42. When the connector element 62 is fully in
position it interrupts light from the pulsing light sources 40a and
40b to their respective connector switch photocells 42a and 42b.
The light source 40 is arranged to be turned on in response to the
absence of light detection by the connector switch photocells 42a
and 42b for a duration exceeding that of the light pulse interval
of the pulsing light sources 40a and 40b. When the light source 40
is turned on, its light passes through those holes 64 in the
connector element 62 which are fitted with a light transparent
substance to energize the photocells 42 which are adjacent the
light transparent holes. The remaining photocells, which are
adjacent the light opaque holes, do not become energized. The
pattern or arrangements of electrical outputs from the energized
and non energized photocells corresponds to the station code; and
this output is used for data recording in the watchman's unit.
FIG. 6 shows in block diagram form the arrangement of components
within the watchman's unit. In the arrangement of FIG. 6 both
station identification and time data signals are inserted into
predetermined memory locations; however the full capacity of only
four 256 bit memories is utilized in the recording of 64 station
checks. Also with the arrangement of FIG. 6, the same station may
be rechecked at different times during a tour and each check will
be properly and unambiguously recorded in the storage means.
As shown in FIG. 6 there are provided four 256 bit memory units 70,
72, 74 and 76. Each memory unit includes eight address terminals
78a . . . 78h which control, according to the arrangement of
signals applied thereto, the locations within the unit where data
information is stored.
Station identification information is generated in binary coded
digital form upon the connection of the watchman's unit to a check
station, as described above. This information is presented in
binary digital form at various outputs 80b . . . 80i of an input
transducer 82. This transducer may, for example, include the
photocells 42 of FIG. 3. The outputs from the transducer 82 are
arranged into two groups 80b . . . 80e and 80f . . . 80i and are
supplied, respectively, to bit select units 84 and 86. These bit
select units each have two address terminals 88a and 88b and,
depending on the particular arrangement of binary signals applied
to these address terminals, the bit select units 84 and 86 will
permit a different one of the applied outputs 80 to pass through to
a single data input line 84a and 86a respectively. Actually, as
will be seen, the binary signals are binary forms of successive
counts from one to four so that the bit selections scan the outputs
80 and successively pass each of them through the selectors to
their single output. The data input lines 84a and 86a are connected
to data input terminals 88 and 90 of the two memory units 70 and
72.
Time data information is generated by means of a clock 92 which
generates a continuous series of accurately spaced impulses. A
binary counter or "Count Down Circuit" 94 receives these pulses and
produces a predetermined submultiple thereof. These divided down
pulses are applied to a time counter 96, which may be a multiple
stage binary register or accumulator having a plurality of output
terminals 98a . . . 98h. The pattern of energization of these
terminals, as in the preceeding embodiments, represents the total
accumulated pulse count from the divider 94; and this in turn
corresponds to the elapsed time since the clearing of the time
counter 96. The first four terminals 98a . . . 98d are connected to
a third bit select unit 100 while the second four terminals 98a . .
. 98h are connected to a fourth bit selector unit 102. These two
bit selector units operate in the same manner to direct different
ones of their applied signals through them to single output data
lines 100a and 102a in accordance with binary signals applied to
address terminals 88a and 88b thereon. These data lines are
connected respectively to data input terminals 103 and 104 of the
memory units 74 and 76.
The eight address terminals 78a . . . 78h of the memory units 70,
72, 74 and 76 serve to direct data signals from the bit select
units 84, 86, 100 and 102 to particular ones of the 256 different
locations within the memory units.
Corresponding ones of the address terminals of each of the memory
units are connected to an associated output terminal 106a . . .
106h of an address counter 108. This address counter has an input
terminal 110 connected through a clock gate 112 to the clock 92. As
clock signals pass through the gate 112 they are accumulated in the
address counter 108 and cause its output terminals 106a . . . 106h
successively to change the pattern of their energization, thereby
successively changing the bit locations within the memory units 70,
72, 74, and 76 which can receive and store data input signals. The
address counter 108 is arranged to count in conventional binary
form with the first terminal 106a corresponding to the least
significant digit and the last terminal 106h corresponding to the
most significant digit. The two least significant digit output
terminals 106a and 106b of the address counter 108 are connected to
corresponding address terminals 88a and 88b of each of the four bit
selector units 84, 86, 100 and 102. It will be appreciated that as
successive pulses are applied to the address counter 108 to step it
through a complete address count sequence, the bit selectors, which
are of a much smaller count capacity, recycle, i.e. scan through
their selection range successively a number of times. It will
further be appreciated that the address counter with its eight
output terminals can produce a total of 256 different addresses,
corresponding to the number of bit locations in each of the memory
units 70, 72, 74 and 76. The bit selector units 84, 86, 100 and 102
on the other hand, are capable of accumulating only four counts, to
direct their four applied inputs in succession to their single
output. Thus, as 256 clock pulses are applied successively to the
address counter 108, 64 4-bit words are successively transferred
from the station identification input transducer 82 and the time
counter 96 into each of the various memory units. Actually, the two
memory units 70 and 72 cooperate by storing different halves of the
8-bit words constituting each complete station identification data
signal, while the other two memory units 74 and 76 cooperate by
storing different halves of the 8-bit words constituting each
complete time data signal.
The two least significant bit output terminals 106a and 106b of the
address counter 108 are also connected to a fourth bit decode
counter 114 which produces a stop pulse for application to a
"SYNCH" circuit 116 each time the address counter 108 has been
stepped through four address changes. Signals from the clock 92 are
also applied to the "SYNCH" circuit 116 and are used to control the
clock gate 112.
The station input transducer 82 is provided with output terminals
80a and 80j connected to a start AND gate 118. Outputs from this
gate are also applied through the "SYNCH" circuit 116 to the clock
gate 112. A "Recorded" indicator light 120 is connected to the
output of the "SYNCH" circuit 116 to record the insertion of data
from the station input transducer 84 and the time counter 96 into
their respective memory units 70, 72, 74 and 76. A pulse generator
122 is provided at the station input transducer to produce the
signals applied to the AND gate 118. A delay circuit 124 is
connected to the output of the clock gate 112; and this circuit
serves to close the AND gate 118 for a duration at least as long as
necessary to complete a station check. This serves to prevent
anomolous readings from transients or other extraneous effects
which might cause different signals to be applied through the
station input transducer 84 while a station reading is being
taken.
The output of the clock gate 112 is also applied to a "WRITE PULSE"
circuit 126 which in turn is connected to write input terminals
128a . . . 128d of each of the memory units 70, 72, 74 and 76.
In operation of the above described system a reset pulse is applied
to a reset terminal 130 of the time counter 96 to clear that
counter at the start of a watchman's tour. As the watchman proceeds
along his tour, the clock produces a continuous series of
accurately timed pulses, and these pulses, as divided down by the
"COUNT DOWN" circuit 94 are accumulated in the time counter 96. The
pattern of energization of the time counter output terminals 98a .
. . 98h which corresponds to elapsed time, is applied to the third
and fourth bit select units 100 and 102.
When the watchman connects his unit to the first station to be
checked, a pulse is generated by the pulse generator 122 and the
station input transducer 82 is caused to energize its station
identification terminals 80b . . . 80i in accordance with a binary
digital code representative of the station identity. This code is
applied to the terminals of the first and second bit select units
84 and 86.
The station input transducer also produces a signal via the AND
gate 118 to a "START" terminal of the "SYNCH" circuit 116. This
allows the next subsequent clock signal to pass through the "SYNCH"
circuit and open the clock gate 112. The following clock signals
then pass through the clock gate and step the address counter 108
also so that it successively addresses different storage locations
in the four memory units 70, 72, 74 and 76. At the same time, and
in synchronism with this address stepping, the signals from the
least significant digit outputs 106a and 106b of the address
counter 108 are applied to the four bit select units 84, 86, 100
and 102 causing them successively to transmit the signals present
on each of their four inputs to different locations within the
associated memory units 70, 72, 74 and 76.
When four clock pulses have occured, the bit select units will have
scanned each of their four inputs. Also at this time, the fourth
bit decode counter 114 will produce a signal at the "STOP" terminal
of the "SYNCH" circuit 116 so that no further stepping of either
the address counter or the bit select units will take place. During
the stepping of these units, the clock pulses which pass through
the clock gate 112 also activate the "WRITE PULSE" circuit 126.
This circuit supplies pulses to write input terminals 128a . . .
128d at each of the memory units 70, 72, 74 and 76 to allow those
units to accept information present on their respective data input
terminals 88, 90, 103 and 104, and to store that data in locations
corresponding to the signal pattern at their address terminals 78a
. . . 78h.
It will be appreciated from the foregoing that it is possible with
the system described herein to store correlated time and station
identification data, each having 8-bit word lengths, into 256 bit
memory units in such a manner that the memory units are used in a
most efficient manner for maximum data storage capacity.
Information may be read out of the memory units when the watchman's
unit is connected to a computer terminal board as in the case of
the preceeding embodiments. In such case address interrogation
signals are applied from the computer terminal board to address
interrogation terminals 132a . . . 132h connected, respectively, to
each of the memory unit address terminals. Write signals are also
applied from the computer terminal board through a write input
terminal 134 to the write input terminals 128a . . . 128d of the
memory unit. Data outputs from the memory units are supplied via
station identification and time data output terminals 136, 137, 138
and 139 respectively.
Having thus described the invention with particular reference to
the preferred forms thereof, it will be obvious to those skilled in
the art to which the invention pertains, after understanding the
invention, that various changes and modifications may be made
therein without departing from the spirit and scope of the
invention as defined by the claims appended hereto.
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